var results = "";
var outcome = "";
function calculater() {
    console.log()
    if (event.srcElement.innerText == "=") {
        return;
    }//按下=，直接跳出函数
    if (event.srcElement.innerText == "C") {
        results = "";
        ioput.innerText = "0";
        return;
    }//按下C，使ioput内容变为0
    if (event.srcElement.id == "ioput") {
        return
    }//当ioput被按下，直接跳出函数

    results += event.srcElement.innerText;
    ioput.innerText = results;

}

function resultcalc() {

    outcome = eval(results) || 0;
    ioput.innerText = outcome;
}